Medical Center database
Non primary-foreign key JOINs
Non-equi JOINs
Non-equi self JOINs
Instruction
Good! We can also use non-equi JOINs in order to, for example, list items added after a particular item or date:
SELECT Item1.Name FROM Items Item1 JOIN Items Item2 ON Item1.DateAdded < Item2.DateAdded WHERE Item2.Id = 3
With this query, we limit the aliased Item2 table to only one record (with Id = 3) and tell our database to show the names of all items that were added before the item with Id = 3.
Exercise
Show the names of all employees who are younger than Mark Gatis.
Stuck? Here's a hint!
Type:
SELECT Emp1.Name FROM Employee Emp1 JOIN Employee Emp2 ON Emp1.Age < Emp2.Age WHERE Emp2.Name = 'Mark Gatis'
